检索结果-南通市图书馆

A Coupled Approach for Fluid Dynamic Problems Using the PDE Framework Peano

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2012年第6期12卷 65-84页

作者： Philipp Neumann hans-joachim bungartz Miriam Mehl Tobias Neckel Tobias Weinzierl Chair of Scientific Computing Faculty of InformaticsTechnische Universitat MunchenBoltzmannstr.381545 GarchingGermany

We couple different flow models,i.e.a finite element solver for the Navier-Stokes equations and a Lattice Boltzmann automaton,using the framework Peano as a common *** new coupling strategy between the meso-and macroscopic solver is presented and validated in a 2D channel flow *** results are in good agreement with theory and results obtained in similar works by Latt et *** addition,the test scenarios show an improved stability of the coupledmethod compared to pure Lattice Boltzmann simulations.

关键词： Spatial coupling Lattice Boltzmann Navier-Stokes Peano

Impact of renewable energies on the operation and economicsituation of coal fired power stations： Actual situation of coalfired power stations in Germany

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers in Energy 2017年第2期11卷 119-125页

作者： hans-joachim KRAUTZ Alexander LISK joachim POSSELT Christian KATZER Department for Power Plant Technology Brandenburg University of Technology Cottbus-Senftenberg 03046 Cottbus Gemany

Due to the fluctuating character of the renewable energy sources the demand of conventional power plants for flexibility is increasing. In the recent years, in Germany there has been a fast rise of production capacity of renewable energies, especially from wind turbines, photovoltaic installations, and biomass plants. The installed nominal power of wind turbines is actually (December 2016) 42 GW and of photovoltaic installations 40?GW. The renewable electric energy production in Germany is about 190?TWh/a, which represents a share of 33% of the yearly demand. The increased need for flexibility affects both the power gradients as well as the minimum load of conventional power plants. Due to this flexibility behaviour, conventional power plants are faced with problems concerning the durability of power plant components, corrosion, more maintenance effort and consequently the overall life expectancy. Another consequence of the increasing share of renewable energies is the decreasing full load operating hours, especially of coal fired and gas power plants. Along with decreasing revenues from the energy exchange market, coal fired power plants are faced with new economically challenges.

关键词： flexible load operation minimal load power gradients power plant maintenance corrosion life expectancy

Metamorphic Evolution of Chloritoid-Bearing Micaschist from the Variscan Elstergebirge: Evidences for Stacking of High-Pressure Rocks in the Saxothuringian Zone of Central Europe

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2020年第3期31卷 425-446页

作者： Gelareh Rahimi hans-joachim Massonne Fakultat Chemie Universitat Stuttgart70569 StuttgartGermany School of Earth Sciences China University of GeosciencesWuhan 430074China

A chloritoid-garnet-bearing micaschist from the southern part of the Elstergebirge was studied to better understand the Variscan orogenic evolution in the Saxothuringian zone of the northwestern Bohemian *** on the textural relations and compositions of minerals,especially of zoned garnet and potassic white mica,a P-T path was reconstructed using contoured P-T *** U-Th-Pb dating of monazite in the micaschist was undertaken with the electron *** micaschist experienced P-T conditions along a clockwise path between 16 kbar at 510℃and 5 kbar at 555℃followed by isobaric heating to about 600℃.Monazite ages range between 315 and 480 Ma with the most prominent maxima and side maxima at 346.0±1.1(2σ),357.3±2.3,and 368.3±1.7 *** older than 380 Ma were related to detrital monazite pointing to a Devonian sedimentary *** ages around 325 Ma were assigned to the isobaric heating by nearby post-tectonic *** high-pressure event,being the result of the collision of Laurussia and Gondwana after closure of the Rheic Ocean,occurred in the Late *** exhumation to 15-20 km(5 kbar)ended probably in the Early *** high-pressure micaschists from the Fichtelgebirge to the Erzgebirge crystalline complexes are suggested to represent a single nappe within a metamorphic nappe *** nappe is composed of metasedimentary slices,which experienced different peak pressures rather than representing a coherent crustal section.

关键词： Saxothuringian micaschist chloritoid garnet monazite dating Variscan P-T path

A Mixed—Mode BIST Scheme Based on Folding Compression

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2002年第2期17卷 203-212页

作者：梁华国 Sybille Hellebrand hans-joachim Wunderlich Department of Computer and Information Hefei University of Technology Hefei 230009. P.R. China Institute of Applied Computer Science University of Innsbruck Austria Institute of Computer Science University of Stuttgart Germany

In this paper a new scheme for mixed mode scan-based BIST is presented with complete fault coverage, and some new concepts of folding set and computing are *** scheme applies single feedback polynomial of LFSR for generating pseudo-random patterns, as well as for compressing and extending seeds of folding sets and an LFSR, where we encode seed of folding set as an initial seed of LFSR. Moreover these new techniques are 100%compatible with scan design. Experimental results show that the proposed scheme outperforms previously published approaches based on the reseeding of LFSRs.

关键词： BIST random pattern testing LFSR folding set

Pressure-Temperature Evolution of a Mylonitic Gneiss from the Lower Seve Nappe in the Handol Area,Central Sweden

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2021年第6期32卷 1496-1511页

作者： Botao Li hans-joachim Massonne Xiaoping Yuan School of Earth Sciences China University of GeosciencesWuhan430074China Fakultät Chemie Universität Stuttgart70569StuttgartGermany

Ultrahigh-pressure metamorphism has recently been reported from various crustal rocks in the Seve Nappe Complex(SNC)in which microdiamonds were ***,in gneiss from the Lower Seve Nappe(LSN),neither any direct petrographic indication for UHP was reported nor the metamorphic evolution was well *** studied a mylonitic gneiss from the Handol area of the LSN and applied phase-diagram modeling and Ti-in-biotite *** on the compositions of garnet and biotite and observed mineral assemblages,a path was reconstructed passing through about 8 kbar and 730℃at prograde ***-pressure and initial retrograde stages occurred at 9.0–10.2 kbar at 745-775℃,and 7–9 kbar at<750℃,*** ultrahigh-pressure evidence was recognized compatible with medium-pressure metamorphism deduced in earlier studies of gneiss from the *** higher peak pressures were reported recently for metamorphic rocks of the LSN,a possible interpretation is that slices or erased blocks were subducted,metamorphosed at different depths,and exhumed in a subduction ***,the dominant gneiss of the SNC experienced only a medium-pressure metamorphism in the upper part of the downgoing Baltica *** from different depth levels were brought together in an exhumation channel located between Baltica and the overlying plate.

关键词： Lower Seve Nappe Swedish Caledonides mylonitic gneiss P-T pseudosection modeling Ti-in-biotite thermometry metamorphic rocks

Effect of HTS Superconductors on Homogeneity of Measurement Field in Low Field Nuclear Magnetic Resonance Detection

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第8期27卷 250-252页

作者：董慧张懿 KRAUSE hans-joachim 谢晓明 State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 Institute of Bio- and Nanosystems Forschungszentrum Jiilich. D-52425 Jiilieh Germany Graduate University of the Chinese Academy of Sciences Beijing 100049

In recent years, superconducting quantum interference devices （SQUIDs） have been demonstrated to be useful in the low field nuclear magnetic resonance （NMR） measurements. The high temperature superconducting （HTS） SQUID used in our experiments has a frequency-independent sensitivity of 40-50fT/Hz^1/2. When a liquid nitrogen cooled LC circuit is employed to form a tuned circuit with the SQUID, the sensitivity of the system can be further enhanced. The LC circuit consists of a capacitor and a coil made of copper wire or HTS tape, which is inductively coupled to the SQUID. However, the homogeneity of the measurement field deteriorates because of the HTS tape coil in the proximity of the sample. In contrast, the thin film SQUID with a washer area of 1 cm^2 has no effect on the NMR signal. Therefore, the impairment of the measurement field homogeneity in the case of different superconducting elements nearby is discussed by examining the free induction decay signals at 9 kHz. It is found that a square superconducting film with an area of i cm^2 may compensate for the inhomogeneity of the measurement field after the adjustment of its position.

关键词： HIGH temperature superconductors NUCLEAR magnetic resonance SUPERCONDUCTING quantum interference devices PHYSICS experiments LIQUID nitrogen SENSITIVITY analysis

Etching Effect on CMP of Different GaN Layers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 276-280页

作者： Siche Dietmar Rost hans-joachim Schulz Tobias Albrecht Martin Institute of Crystal Growth Max-Born-Str. 2 12489 Berlin Germany

Chemical mechanical polishing (CMP) was used to etch various GaN materials, such as GaN layers on sapphire and silicon carbide substrates grown by metal-organic chemical vapor deposition and thick GaN layers grown by physical vapor transport. It was found that CMP could reveal the dislocations in GaN surfaces due to a selective etching component. After the optimization of CMP condition, the surface finish improved and the subsurface damage was almost completely removed, demonstrated by atomic force microscopy and an electron back-scattered diffraction technique. This study established the correlation between the dislocation density and film quality. The crystalline perfection and optical properties of GaN layers were characterized by high resolution X-ray diffraction and photoluminescence.

关键词： surface etch pits CMP GaN

Magnetic resonance imaging in children and adolescents with chronic inflammatory bowel disease

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第5期20卷 1180-1191页

作者： hans-joachim Mentzel Steffen Reinsch Monika Kurzai Martin Stenzel Section of Pediatric Radiology Department of Radiology University Hospital Jena- Friedrich-Schiller-University Jena Section of Pediatric Gastro-enterology Department of Pediatrics University Hospital Jena Friedrich-Schiller-University Jena

Inflammatory bowel diseases(IBD) represent challenges, both from a diagnostic, and therapeutic point of view. Deep-seated anatomic structures are difficult to assess by ultrasound technique alone. As radiation-free alternative cross-sectional imaging method, magnetic resonance imaging of the intestinal structures is costly and time-consuming. Examination of pediatric patients imply additional considerations: reduction of body motions in younger children and consideration of the most appropriate preparation, and examination technique. The demanding Sellink technique is the only means for appropriately distending the lesser intestine in order to detect small bowel strictures. Oral intake of contrast medium(CM) alone shows its limitations regarding distensibility. The need for intravenous contrast media application needs to be considered, too. Active inflammation of both intestinal wall, and mesentery can be demonstrated accurately. Nevertheless, viable alternatives to CM application is desirable, considering non-negligible adverse reactions. Recent data suggest diffusion weighted imaging might fill this diagnostic gap. Irrespective of sequence technique chosen, bowel movement remains a major obstacle. Antispasmolytics in their function as smooth muscle relaxants help in improving image quality, however, their use in children might be off-label. Optimal preparation for the examination and appropriate imaging technique allow for diagnosing typical patterns of changes in IBD, such as bowel wall thickening, ulcers, mural stratification, strictures, creeping fat, and comb sign, and lymphadenopathy. The article gives a detailed overview of current significance of magnetic resonance imaging pediatric patients suffering from IBD, considering indications, limitations, and safety aspects.

关键词： Children, Adolescents, Inflammatory bowel disease, Crohn’ s disease, Ulcerative colitis, Magnetic resonance imaging, Enterography

Biased dispersal of Metrioptera bicolor, a wing dimorphic bush-cricket

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2018年第2期25卷 297-308页

作者： Ina Monika Margret Heidinge Silke Hein Heike Feldhaar hans-joachim Poethke Field Station Fabrikschleichach University of W（Jrzburg Rauhenebrach Germany W~sseri 8 CH-8816 Hirzel Switzerland Department of Animal Ecology I University of Bayreuth Bayreuth Germany Bavarian State Institute for Viticulture and Horti- culture Bee Research Center An der Steige 15 97206 VeitshSchheim Germany

In the highly fragmented landscape of central Europe, dispersal is of particular importance as it determines the long-term survival of animal populations. Dispersal not only secures the recolonization of patches where populations went extinct, it may also rescue small populations and thus prevent local extinction events. As dispersal involves different individual fitness costs, the decision to disperse should not be random but context- dependent and often will be biased toward a certain group of individuals （e.g., sex- and wing morph-biased dispersal）. Although biased dispersal has far-reaching consequences for animal populations, immediate studies of sex- and wing morph-biased dispersal in orthopterans are very rare. Here, we used a combined approach of morphological and genetic analyses to investigate biased dispersal of Metrioptera bicolor, a wing dimorphic bush-cricket. Our results clearly show wing morph-biased dispersal for both sexes of M. bicolor. In addition, we found sex-biased dispersal for macropterous individuals, but not for micropters. Both, morphological and genetic data, favor macropterous males as dispersal unit of this bush-cricket species. To get an idea of the flight ability ofM. bicolor, we compared our morphological data with that of Locusta migratoria and Schistocerca gregaria, which are very good flyers. Based on our morphological data, we suggest a good flight ability for macropters of M. bicolor, although flying individuals of this species are seldom observed.

关键词： aspect ratio dispersal traits flight muscle ratio Metrioptera bicolor sex-biased dispersal wing load wing morph-biased dispersal